Please suggest serene, restful jazz recordings

Bill Evans Trio - Waltz For Debby
Bill Evans Trio - Live @ Village Vanguard
These are the definitive piano trio LPs, both featuring phenomenal bass of Scott LaFaro

Miles Davis - Sketches of Spain
This LP shows off Gil Evans skills of orchestration and creates a sublime sound that stands the test of time

Ray Brown & Laurindo Almeida - Moonlight Serenade
The inter-twining of Round Midnight & Moonlight Sonata is to die for...Cheers,
Spencer

John Coltrane --> Ballads

Earl Klugh? Pretty tame, mellow stuff.

Antonio Forcione's duet album with Charlie Haden. Thoughtful, lovely and melodic.
BerkeleyBob

There are already four recommendations on Charlie Haden/Pat Metheny's "Beyond the Missouri Sky". Make that five. This particular recording fits all your criterias. Quality of recording is excellent and the tunes are serene, peaceful and quiet as you can get. As mentioned by the previous poster Gdoodle, this CD is a must have. My favourite tracks from this album in order are "Cinema Paradiso(love theme)", "The Moon Song" and "Our Spanish Love Song".

In fact, most of Pat Metheny's works are all very good. Even the older recordings which date back to the late 70's under ECM are all excellent in quality albeit a little lightweight in the bass. "Offramp" and "Imaginary Day" are my next favourites from Metheny. There are a few not-so-quiet tunes in "Imaginary Day" but the overall quality of this album can be considered as excellent. If you are only interested in quiet background music, "Trio 99>00" may put you to sleep.

Earl Klugh is another artist that worth a mention.

David Benoit is another one of my favourite contemporary jazz pianists, although some of his pieces may be termed as 'piano banging' by your standards. I would however describe it as a crescendo which adds more life into the music.

Fourplay is another jazz group worth checking out. Mostly mellow stuff. "Heartfelt" and "Fourplay" are my favourites.